中文摘要：

上部开口环形液池在水平径向温度梯度作用下会出现内部温度和自由面的振荡,本文研究了二者发生的临界条件.环形液池内柱加热外壁制冷,以0.5℃/min的速率线性升温得到水平径向温差,T型热电偶测量液层内部单点温度,高精度激光位移传感器测量液层自由面某点形变.随两端温差增加,当超过某一临界温度△Tcr时,开始出现振荡.实验结果表明,对同一种硅油,两种振荡的临界条件随液层厚度具有相同的变化趋势.对不同普朗特（Prandtl）数（Pr）的硅油,振荡临界条件临界马兰哥尼数（Macr）随着邦德数（Bo）的增加而变大.本文工作是中国科学院科学先导专项SJ-10返回式科学实验卫星项目-热毛细对流表面波空间实验研究的地面研究结果,该工作为空间实验提供前期的基础科学研究数据和实验保障.

英文摘要：

The temperature oscillation and the free surface deformation are two essential phenomena for the fluid with free surface. In this paper, an annular pool with upper opening is constructed to obtain critical conditions of the onset of temperature oscillations and free surface oscillations when the horizontal radial temperature gradient is given. The experimental pool is cooled from the outer cylinder walls by 6 semiconductor coolers and linearly heated from the inner cylinder walls at the rate of 0.5℃/min, resulting in a horizontal radial temperature difference. The T-type thermocouple is used here to measure the temperature at a single point in the liquid layer and the free surface deformation is obtained by the CCD （charge-coupled device） displacement sensor at the same time. The temperature and the free surface begin to oscillate when the temperature exceeds a threshold value with the increase of the temperature difference. Experimental results show that for the same kind of silicone oil, the Macr is proportional to the Bond number; the enhancement of the buoyancy convection can stabilize the whole flow; on the other hand, with the same thickness, the silicone oil of 1.5cSt has a largerMacr than that of 2cSt; the decrease of the viscosity makes the flow more stable.